The present invention relates to a structure of an electronic throttle system for controlling air intake in internal combustion engines.
The following five prior arts are known relating to arrangement of a valve shaft, an motor, a clutch, etc. in the conventional structure of a throttle body.
1. Cooling type throttle actuator (JP A 2-55842)
A coolant passage line is provided inside a motor to provide a positive cooling effect at all times regardless of engine operating condition.
2. Throttle actuator (JP A 59-226244)
A drive motor, a solenoid clutch mechanism, a return spring for restoring a throttle valve, and a photo-encoder for detecting rotation of a throttle shaft are housed into a one-piece structure for a reduction in size.
3. Throttle controller (JP A 2-27123)
Components such as an operation lever and a control lever are dispersedly arranged at one end and the other end of a throttle body for a reduction in size, and a lost motion spring is provided to keep the operation lever from being affected by control of an motor.
4. Device for operating throttle valve of internal combustion engine (JP A 1-15173)
A solenoid clutch is provided between a motor output shaft and a throttle valve shaft. The solenoid clutch is connected during normal operation and disconnected in failure of a controller and upon cut-off of a motor current, so that emergency travel operation is enabled without using any expensive logic circuit for safety.
5. Device for controlling vehicular internal combustion engine (JP A 1-301934)
A solenoid coupling is provided to completely disconnect an accelerator lever from a throttle valve during normal operation, thereby eliminating an influence of torque on a servo motor.